[nanoPost] Nanosensors

Company USA

Biosensor

The nanoporous silicon-based biosensor technology detect selected bacteria, salmonella and e-coli. This license also provides the Company with the first right of refusal for other bacteria which may be developed. The Company initiated the design and engineering of their first biosensor product for the bacteria e-coli promptly after the license agreement was executed.

The product consists of two core functional parts. First, the product design incorporates a disposable housing unit in which the actual sensor device would be mounted on a secured and sealed platform and a separate, external data acquisition unit. The sensor housing unit has been designed to incorporate the necessary electrical leads to transmit the signal from the sensor to the external data acquisition unit. The data acquisition unit has be designed to accept the output signal from the disposable housing unit, convert the signal to the appropriate format and to display the results. The prototype of the first biosensor product has been built and tested. The Company has finalized the design of the first prototype and limited quantities of the disposable unit and data acquisition unit have been produced by a third-party manufacturer.

The Company expects that their next nanoporous silicon-based biosensor product will be to detect the bacteria, salmonella. On average Salmonella sickens 40,000 and kills 600 people a year in the United States. The United States Department of Agriculture estimated the minimum annual cost of illness caused by salmonella bacteria in 2005 to be $2.3 billion, including $2.1 billion for premature death, $181 million for medical care, and $89 million in lost productivity. The Company does not anticipate major changes on the physical designs for the housing unit or the data acquisition unit used to detect e-coli in order to make it adaptable for salmonella. The changes will primarily reside in functionalizing the nanoporous silicon for salmonella rather than e-coli.

Nanoporous Silicon-based Sensors for Other Bacteria.

The Company's research plan is directed toward developing biosensors for other bacteria. As previously mentioned, their license provides them with a first right of refusal for using the licensed technology for the detections of other bacteria. The research effort will be conducted by their licensor with funding support provided by the Company and will focus on determining the host molecule which will interact with the selected targeted bacteria and developing the method for attaching such host molecules to the nanoporous silicon.

Future Sensor Products 
   
Porous Silicon Electronic Addressed Arrays

The Company’s research indicates that sensors based on porous silicon will offer enhanced sensitivity, reduced power demands and lower cost. Porous silicon based sensors could be integrated into electronic equipment and used to build sensing arrays, because they are based on silicon wafers, manufactured using integrated circuit production techniques and operate at room temperature using low voltages. These sensing arrays are analogous to the manner in which cellular phone networks and their towers are set up, except that our sensing arrays will be designed to protect certain defined geographical areas.

The Company recently announced that we will commence an evaluation to determine the optimal practical physical characteristics of porous silicon for our next generation of sensors. The Company has constructed an apparatus for the electrochemical silicon etching process which will be used to produce porous silicon. The initial evaluation of the process will be conducted with 4-inch silicon wafers to optimize porosity.

The porous silicon based sensors will be fabricated from porous silicon chemically altered to bind only to a specific BCX agent and embedded between measurement electrodes. Arrays will be fabricated from individual porous silicon fibers coated for BCX agent specificity and electrically connected to processing devices to determine the presence and identity of agents. Porous silicon exhibits a large change in electrical conductivity on exposure to trace amounts of the vapor characteristic of BCX materials due to the large surface area per volume ratio. Sensitivity to parts per billion or less concentration is anticipated allowing stand-off detection of an explosive.

Carbon Nanotube Sensors

The Company’s studies have found that carbon nanotube technology is promising for chemical and biological detection. The carbon nano-tube sensors can be built to facilitate distributed, or wireless, gas sensing networks, leading to more efficient multi-point measurements, or greater convenience and flexibility in performing measurements. In addition, carbon nanotube chemical and biological sensors would be suitable for sensing different species of interest. Such sensors could be configured in the form of an array to comprehensively and cost-effectively monitor multiple species. As mentioned previously, the FETs are sensors on silicon chip configuration in which the carbon nanotubes are connected between two junctions on a silicon substrate. These types of sensors are functionalized by placing a minute drop of host molecule close to the carbon nanotubes to interact with the target agent, including bacertium. Once the targeted agent interacts with the host molecule, the electrical signal of the sensor is altered.

The Company has initiated a test program to characterize carbon nanotube FETs to detect targeted agents. The characterization program will be conducted by the licensor of the Company’s nanoporous silicon-based sensors. The Company believes that the use carbon nanotube FETs offers several advantages, including higher sensitivity for detection and a shorter development cycle for sensor development.

The company believes that due to these qualities, sensors based on carbon nanotubes can also improve the detection of vapors from explosives. The Company believes that devices can be developed where sensors are arranged in arrays that can be tuned to respond to the presence of specific explosives and biological and chemical agents. Each nanotube would be anchored to a metalized silicon substrate at one end of the tube and chemically enhanced to bind only to a specific molecule at the other end. The tube experiences a lowering of the frequency when extra mass is attached to the functional end of the tube. The presence of a mass of an absorbed agent, such as Anthrax, on the free end of the nanotube will produce a measurable frequency shift. The selective binding of agents to the chemically enhanced nanotubes will allow the array to sense the presence of different BCX agents.